I've always just unhooked them both when I changed batteries, but now someone has made me paranoid about it. So I thought I should ask. I already cleaned the negative because I know that's a safe bet. When I clean the positive one, does the negative need to be unhooked also or can I just leave it hooked up while I take the positive off to clean it? Thanks!
2007-08-12 06:39:25 · 11 answers · asked by Someday Soon 2 in Cars & Transportation ➔ Maintenance & Repairs
ReportTheDodgeman:
Honey, I think you forgot your medication this morning.
2007-08-12 06:46:04 · update #1
Curious as to what you were told to make you somewhat paranoid about this.
No, it really doesn't matter as to which one you disconnect first or clean first or if you leave one connected as long as your tools do not touch the frame or ground while working on the positive terminal as they will cause sparks and damage when they short out. However, if you have a vehicle with two batteries installed (RV, motorhome, etc...) then you should disconnect the negative on both batteries first and leave them disconnected while you do the positive cables because if you should accidently drop or allow the positive cable to touch any part of the vehicle's frame or negative post, you will cause a short to the other battery's power. Disconnecting the negative terminal first and leaving it off is always the perferred method for any service work to be done.
Regardless of which terminal you hook up last (positive or negative) you have the possibility of a spark depending on if there is sufficient current draw from the vehicle at the time it is connected. You should always do this in a well ventilated area to reduce the chance of exploding the hydrogen gases from the battery.
2007-08-12 06:46:57 · answer #1 · answered by Denver Al 7 · 0⤊ 2⤋
Proper way to hook up and unhook a battery is to disconnect the negative cable first then the positive. When you go to reattach, hook the positive up then the negative. The reason is you don't want to cause a spark to happen around a battery. Sparks have been known to ignite fumes coming from batteries. Leaving them both disconnected while cleaning the terminals and cables is fine. Just make sure you attach them positive first then negative.
2007-08-12 06:49:36 · answer #2 · answered by gearnofear 6 · 2⤊ 2⤋
The reason you unhook the negative first is because it won't matter if you short the wrench to ground while you're working on that one, and once it's off it won't hurt if you short the positive cable to ground.
2007-08-12 07:27:20 · answer #3 · answered by Nomadd 7 · 0⤊ 1⤋
Since most batteries are negative ground, if you have a wrench on the negative side and happen to touch metal nothing will happen. If you are on the positive side, and touch metal you will get sparks and a short. So negative first for safety reasons.
You can do the positive with the negative hooked up, but be aware of what you are doing and don't touch any metal with your wrench.
2007-08-12 06:48:25 · answer #4 · answered by oklatom 7 · 1⤊ 2⤋
The shop Manuels I use all state disconnect Neg.
first;also the newer cars need power to Computer
all time; I have a keep alive device that plug into
house current it changes to dc connect pos and neg cables,and You will not have performance problems when you reconnect,The device is realative cheap;
2007-08-12 06:51:51 · answer #5 · answered by section hand 6 · 1⤊ 1⤋
yeah unhook the negative first this will prevent you from shorting out the positive side when removing it put them back on in reverse attaching the positive side first
2007-08-12 06:52:46 · answer #6 · answered by Big-J 1 · 2⤊ 1⤋
as a safe practic allways remove the negitive cable first and reconnect last because the spark can trigger the air bag system and the security circuits and ofcourse the stereo memory... clean the clamps the post and the top of the battery the battery will last longer
2007-08-12 06:50:02 · answer #7 · answered by James K 2 · 2⤊ 2⤋
The alternator may be working fine on the test machine but not in the truck due to a loose wire connection.The large red wire on the back goes directly to the battery.One of the two smaller wires goes to the ignition switch.The other goes to the gauge or light.
2016-05-20 22:18:55 · answer #8 · answered by ? 3 · 0⤊ 0⤋
I always unhook the negative first and hook it back up last.
I cannot remember why or where I learned it. It is just the way I have always done it.
2007-08-12 06:48:13 · answer #9 · answered by Dionannan 5 · 3⤊ 2⤋
Unhook them both no matter which one first.
Remember the big post is for the Pos+ and little for -
life is easy when you don't let folks make you paranoid.
2007-08-12 06:46:46 · answer #10 · answered by reddcobalt07 3 · 0⤊ 3⤋